Encyclopedia of Computer Science and Technology

Maes, Pattie 289ing coding. However, a given procedure appears in the codeonly once, although it may be called upon from many differentparts of the program. A macro, on the other hand, is not“called.” Each time it is mentioned, the macro is replaced bythe corresponding instructions. Thus macros increase thesize of the source code.Many programmers today prefer using functions withthe appropriate code rather than macros. Using functionssaves space, since each function’s code need only appearonce. Although there is some processing overhead at runtimein calling the function, the function approach alsoensures that the data sent to the function will be checked tomake sure it is of the proper type. The macro, on the otherhand, usually leaves it up to the programmer to make surethe data type being used is appropriate.Application MacrosThe term macro is also used with applications software.Here it can mean a series of commands (such as cursor positioningor text formatting) that are recorded and assignedto a certain key combination. For example, a word processoruser might define a macro called Letter and record thekeystrokes and/or mouse movements needed to open a newdocument, insert a letterhead from a file, update the date,insert a salutation, and position the cursor to continue writingthe letter. The recorded keystrokes might be assigned tothe key combination Control + L.More elaborate macros can be written to automate complextasks in spreadsheets and word processors. Microsoftprovides an entire language, Visual Basic for Applications(VBA), for writing macros for its Office products.Further ReadingGonzalez, Juan Pablo, et al. Office VBA Macros You Can Use Today:Over 100 Amazing Ways to Automate Word, Excel, PowerPoint,Outlook and Access. Uniontown, Ohio: Holy Macro! Books,2005.Jelen, Bill. VBA and Macros for Microsoft Office Excel 2007. Indianapolis:Que, 2007.Kochan, Stephen. Programming in C. 3rd ed. Indianapolis: Sams,2004.“Preprocessor Directives.” Available online. URL: http://www.cplusplus.com/doc/tutorial/preprocessor.html. AccessedAugust 14, 2007.Maes, Pattie(1961– )Belgian/AmericanComputer ScientistPattie Maes is a pioneer in the creation of software agents,intelligent programs that work with people to help themfind what they need online, whether it is relevant newsstories, a vacation itinerary, or a good place for a romanticdinner for two in San Francisco.Born June 1, 1961, in Brussels, Belgium, Maes was interestedin science (particularly biology) from an early age.She received bachelor’s (1983) and doctoral (1987) degreesin computer science and artificial intelligence from the Universityof Brussels.In 1989 Maes moved from Belgium to the MassachusettsInstitute of Technology, where she joined the ArtificialIntelligence Lab. There she worked with an innovativeresearcher who had created swarms of simple but intriguinginsectlike robots (see Brooks, Rodney). Two years laterMaes became an associate professor at the MIT Media Lab,famed for innovations in how people interact with computertechnology (see MIT Media Lab). There she foundedthe Software Agents Group to promote the development of anew kind of computer program.These programs (see software agent) have considerableautonomy and intelligence. Like a human travel or realestate agent, an agent program must have detailed knowledgeof the appropriate area of expertise; the ability to askthe client questions about preferences, priorities, and constraints;and the ability to find the best deals and negotiatewith service providers.Maes’s goal has been to create software agents who thinkand act much like their human counterparts. To carry outa task using an agent, the user does not have to specifyexactly how it is to be done. Rather, the user describes thetask, and the software engages in a dialog with the user toobtain the necessary guidance.A software travel agent would know—or ask about—such things as how much the user wants to spend andwhether he or she prefers sites involving nature, history, oradventure. It would also ask about and take into considerationconstraints of budget, travel time, comfort, and so on.The software agent would then use its database and proceduresto put together an itinerary based on the user’s needsand desires. It would not only know where to find the bestfares and rates, it would also know how to negotiate withhotels and other services. Indeed, it might negotiate withtheir software agents.In 1995 Maes cofounded Firefly Networks, a companythat attempted to create commercial applications for softwareagent technology. Although the company was boughtby Microsoft in 1998, one of its ideas—“collaborative filtering”—canbe experienced by visitors to sites such as Amazon.com.Users in effect are given an agent whose job it is toprovide recommendations for books and other media. Therecommendations are based upon observing not only whatitems the user has already purchased, but also what elsehas been bought by people who bought those same items.More advanced agents can also tap into feedback resourcessuch as user book reviews on Amazon or auction feedbackon eBay (see social networking).A listing of Maes’s current research projects at MIT conveysmany aspects of and possible applications for softwareagents. These include the combining of agents with interactivevirtual reality, using agent technology to create charactersfor interactive storytelling, the use of agents to matchpeople with the news and other information they are mostlikely to be interested in, an agent that could be sent into anonline market to buy or sell goods, and even a “Yenta” agentthat would introduce people who are most likely to make agood match.